KHOA HOC C 6 N G NGHE
AIMH HUOIMG C U A D O CHilM T H U H A I DEIM IVIOT S O D A C TilMH L Y H O A C U A Q U A HOIMG T H A C H T H A T
Nguydn Thi HanhS Vfl Thi Nga^
T6MTAT
Muc dich cua nghien cim nay nhdm xac dinh anh hudng ciia cac do chin thu hai den mot sd dae tinh ly hda dae trtmg va kha nang chin cua qua hong Thach That {(Diospyros kakiT\mn\i) de tir do dua ra then diem fhu hai thich hpp nhat doi vdi loai qua nay. Cac dae tinh ly hoa dupe xac dinh bao gdm: cudng do hd hap, kich thirdc, khdi luong, do cirng, mau sdc, ham luong chat kho hda tan tdng sd, ham luong dudng tdng sd, ham lugng axit tong sd va ham lugng tanin cua qua hong. Kdt qua cho thay, dp chin thich hop nhat de thu hai qua hong la khi qua cd num mau vang xanh tmn, mau qua vang (>80%) va cd mau vang hoi xanh d duoi qua (<20%), qua ciing gidn, vi rat chat, chua ngot, miii chua ro, dat 100-110 ngay tudi tir khi dau qua.
Tir khda: Qua hong, do chin thu hai, cudng do ho hap, sau thu hoach.
I.DATVANDE
Cay hdng {Diospyros kaklThmib) Id mdt trong nhiing loai cay an qua quan trong cua edc nude chau A thudc mien dn ddi va can nhidt ddi nhu Trung Qudc, Nhat Ban, Trieu Tien, Viet Nam,...a Vidt Nam, hdng duoc trdng khdp moi noi trong ca nude nhtmg phd bien nhat la tir Ha Tinh trd ra ngodi Bac. Hdu het d mdi vimg deu ed nhiing gidng hdng dae tnmg nhu hdng Thach That (Ha Ndi), hdng Nhan Hau (Hd Nam), hdng Hac Tri (Lang Son).
Qua hdng chin do la mdt loai qua hd hap ddt hien, cd kha nang tu chin sau thu hoach. Khi qua chin hodn todn cd mdu do mong, mdm, vi rat ngot, mtii rdt thom, khdng bi chat, dd ddng tach mim va bdc vd qua. Tuy nhidn, viee lua chon do chin thu hoach cua hdng sao cho qud trinh chin sau thu hoach cila qua dat ehdt luong cao phu hop vdi muc dich tieu thu, su dung can phai dupe nghien eiiu, danh gid ky ludng.
Dd chin thu hdi la mdt ydu td rat quan trong trong viec xdc dinh thdi gian tdn trii vd chat luong thdnh pham cua rau qua ndi chung va qua hdng ndi ridng. Qua dupe thu hoach qud sdm hoac qua mudn dd bi rdi loan smh ly hon la qua dupe thu hoach vdo giai doan cd do trudng thdnh thich hop [1, 2, 3]. Ddi vdi qua hdng, thdi diem thu hoach quydt dmh rat nhieu den mau sac eua qua (Camelo, 2002) [4]. Cung vdi do la su anh hudng den kich thudc qua vd su bien
ddi mdt sd chi tieu ly hda quan hpng nhu ham luong dudng tdng sd, ham luong axit, ham Itrpng tanin...Dieu do quyet dmh phan Idn ddn ehdt lugng sau thu hoaeh ciia qua hdng Thach That.
Trong pham vi nghien ciiu nay da nghien ciiu dnh hudng cua cac dp ehin thu hdi den mdt sd dae tinh ly hda qua hdng Thaeh That (Diospyros kaki Thunb.) tii dd dua ra dp chin thich hpp nhdt khuydn cdo thdi gian thu hoach hop ly ddi vdi qua hdng.
2 . NGUYEN UEU VA PflUONG PHAP NGHEN CUU 2.1. Nguydn lidu nghidn ciiu
Nguyen lieu qud hdng thudc gidng hdng Thach That duoe trdng va thu hoach tai huydn Tan Yen, Bdc Giang. Qua hdng duoc lay mdu vao ehinh vu thu hoach thdng 10 nam 2016 va 2017, cd do hidi 90 - 125 ngay ke tir khi dau qua. Hdng duoe thu hdi nhe nhdng vao budi sang trong dieu kien khd rdo. Dung kdo cdt each cudng khoang 1 cm, bd la. Xdp qua vdo trong thung xdp due Id va van ehuyen ve phdng thi nghiem. Qua dupe bd tri thi nghidm trong ngay. T ^ phdng thi nghiem, hdng dugc phan thdnh 4 dd chin DCl, DC2, DCS vd DC4 theo mdu sdc qua dd xdc dinh mdt sd dae tinh ly hda, trong dd DC4 la mdu duge nghidn cim khdo sat de lam ddi chting so sdnh vdi edc do chin DCl, DC2 va DC3.
2.2. Phuong phdp nghidn ohi 2.2.1. Phuong phap bd tri thi nghiem a. Xic dinh inh hudng cua do ehin thu hii den mot sd dae tinh ly, hda vi khi nang chin cua qua hdng sau thu hoach
' Vien Cdng nghe Sinh hoc va Cdng nghe Thirc pham, Trudng Dai hoc Bach khoa Ha Noi
^ Vien Ca dien ndng nghiep vii Cdng nghe sau thu hoach Email: [email protected]
35
KHOA HOC CONG NGHE
Cac mau thi nghiem tmmg bag voi cac dp chin DCl. DC2, DCS va DC4, khdi luong 2 kg/mau. Tidn hanh xac dinh mdt sd chi heu ly, hda cua qua ngay sau thu hoach va xac djnh khd nang tu chin d dieu kien thuong (nhiet dp 25-30^^. RH 65-75*). Tidn hanh theo doi va danh gia qud trinh chin cua cac mdu. Phan tich chat lugng cac mdu d thoi didm qua chin hodn loan. Cac chi tidu chat lupng dugc ddnh gid gdm: kich thudc (dirong kinh, chidu cao); khdi lugng; do ciing; man sdc; ham lugng chat khd hda tan tdng sd (CKHITS); ham lupng duong tdng sd;
ham lupng axit hiiu co tdng sd; ham lugng tanin va chat lugng cam quan cda qua. Mdi thi nghiem dupe 1 ^ lai 3 lan va d cimg mdt thdi diem.
b. Xac dinh inb huong aia do chin thu hii cuong do ho hip aia qua hdng sau thu hoach
Hdng thu hoach d 3 do chin DCl. DC2 va DC3 (nhu mue a) dupe xac dinh cuong dp hd hap d didu kien tiiuong (nhiet dd 25-30'-C, RH 65-75"^). Su dung 3 hop nhua cd ndp gioang kin dung tich 5500 ml chiia cac mdu TN2.1, TX2.2, TN2.3 tuong ung vdi cac do chin: DCl, DC2, DCS, khdi lugng 1,2 kg/mdu. Theo doi va do cudng dp hd hap trong 10 ngdy vdi tdn suat 1 lan/ngdy.
2.2.2. Phuong phip phan ti'ch cbdt luong a. Phuong p h ^ ldy mau qua ttroi theo T C \ ' \ 5120-90
b. Su bien doi man sac vd qua dupe do bdng may do mau Minolta CR-300 cua Xhat
c. Danh gia ehdt lugng cam quan bang phuong
phi^ cam quan md ta
d. Xac dinh ham lupng CKHTTS ( Bx) •- Sit dung khiie xa ke Atago Model PAL-a (C i ; ''^^^- ^ ^ san xuat Atato, .Nhat. Thang do: 0 - 6is
e. Xae dinh ham lirpng axit tdng =d (%) theo 1C\'S 5483 -1991 (tinh theo axit malic)
t Xdc dinh ham luong tanm bdng phuong ph^
Kalipecmanganat (56)
g. Xac djnh ham luong duong tdng sd theo phuong phap Graxianop (90
h. Xac dinh do ciing bdng mdy do dp ciing FT 327 (Italia). Sir dung ddu do 8 mm, don vi kg/cm^
L Xac dinh cudng do hd hdp ciia hdng theo phuong phap km: Su dung thiet bi Illinois Instniment Model 6600.
2.2.3. Phuong phap xd ly sd heu: Ket qua dn n g h i e m dirpc p h a n tich A N O V A v a k i e m dinh LSD (590 b d n g p h d n m d m t h d n g k e SAS 610.
3. KET QUA VA THM LUAN
3 . 1 . P h a n loai h o n g t h e o d p c h i n t h u h a i D u a vao bidu h i d n b e n n g o a i c u a q u a ( c h u ydu li m a u s d c ) , h d n g d u g c p h a n loai t h d n h 4 d p c h i n (DQ n h u t r o n g b a n g 1. T r o n g d d , D C 4 la d o e h i n m a h M ^ b d t d a u c h u y e n s a n g giai d o a n c h i n , q u a c d m a n cam d d v a m e m . Khi c h u y e n s a n g D C 4 . q u a t h u d n g hi c h i m , e h u p t v a m d t sd lodi c d n t r i m g a n , m a t khac q u a t h u o n g r u n g t r u d c k h i c h i n g a y t d n t h a t Idn. Vi vay. p h a i t h u h o a c h h o n g t n r o c k h i q u a c h u y e n s a i ^ D C 4 .
B a n g 1. D a e d i d m c a m q u a n , h i n h thai ciia q u a h d n g liieo d o c h i n t h u h a i
D a e i N u m v a n g x a n h tiroi , N u m v a n g x a n h tuoi X u m q u a m a u v a n g j N u m q u a m a u v a n g d i e m M a u x a n h s a n g M a u q u a v a n g (>SO"''J x a n h tuoi, : x a n h , h o i n a u c a m Q u a Cling, g i o n ' va c o m a u v a n g h o i [ M a u q u a v a n g c a m M a u q u a c a n d o q u a n ' ^'i r a t chat, k h d n g ! x a n h d dit q u a t r e n t o a n q u a . I Q u a h o i m d m
n g o t (<20^) Q u a b d t ddu h o i m e m ' Vi c h a t , h o i n-j
36 NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THANG - 2019
KHOA HOC CONG NGHE Miii: chua rd Qua Cling gidn,
Vi rat chat, chua ngpt Mtii chtra rd
Vl rat chat, chua ngpt Mtii chua ro
Miu: hoi thom
(Ghi chd-Do tudi thu hoach duac nhdm tie gii tham khao ngudi ti-dng tai huyen Thaeh That, Ha Ndi) Qua hdng dugc thu hoaeh d 3 dp ehin DCl, DC2
va DC3 dupe nghien ctm dae diem ly, hda va kha nang tu chin sau thu hoach (so sdnh vol DC4) de xde dinh do ehin thu hdi phti hgp.
3.2. Anh hudng ciia dO chin thu hai ddn mOt sd dae tinh ly hda cua qua hong
Bang 2. Anh hudng dp chin thu hdi ddn mdt sd dae tinh ly hda ciia qua hdng
Trong qua trinh sinh trudng cua rau qua, bdn canh su thay doi thanh phan hda hgc la sir ttiay ddi rd ret ve cde chi tieu vat ly nhu kich thudc, su thay ddi man sdc, khdi luong,... Qua hdng thu hoach theo dp chin dupe phan tich mdt sd dae tinh ly, hda nhu trong bang 2.
TT 1
2 3
4 5 6 7
Dae di^m Kich thuac - Duong kinh (nmi) - Chieu cao (mm) - Khoi luong (g) 0 6 Cling (l^g/cm^
Mau sac L' a' b*
Ham luong CKHTTS (°Bx) Ham lirong axit hiru co TS (%) Ham luong duong TS (%) Ham lucmg tannin (%)
DCl 57,8 ±1,9 55,1 + 1,0 101,4 ±3,3 4,4 ± 0,4 65,85 ±1,11
4,85 ± 1,49 59,27 ±1,7 28,4 ± 0,8 0,29 ±0,03 10,64 + 0,04 23,9 ±0,21
DC2 66,7 ± 0,5 61,5 ±1,3 145,2 ± 3,5
3,9 ±0,2 62,48 ± 0,86 13,94±1,41 56,01+0,72 22,1 ±1,1 0,29 ±0,01 12,53 ±0,02 17,12 ±0,64
DC3 66,6+1,2 62,6 ± 0,3 147,8 ± 2,2
1,6 ±0,4 55,80 ±0,81 23,34 + 0,77 50,89 + 0,41 19,5 ±1,2 0,23 ±0,03 12,89 ±0,05 15,55 ± 0,26
DC4 67,02 ± 0,8
61,6±1,3 151,5 ±1,9
<0,5 50,94 ±5,13
31,09 ±0,8 35,18 ± 1,24
17,3 + 1,0 0,16 ±0,01 13,03+0,11 10,46 ±0,26 Kdt qua d bang 2 eho thay, qua d DCl cd kich
thudc va khdi lugng nhd hon han so vdi cac dp chin cdn lai. O DC2, DCS vd DC4, qua cd kich thude va khdi lugng khde bidt khdng ddng kd, vdi dirdng kinh, chieu cao va khdi lugng trung binh lan Itrgt la 66,8 mm, 61,9 mm va 148,2 g. Nguydn nhan la khi bat dau d DC2 qua hdng da phat trien dn dinh ndn khdng cd su gia tang dang ke ve kieh thudc va khdi lugng qua d edc do ehin tidp theo.
Ve mdu sdc, chi sd L* va b* giam ddn, ddng thdi chi sd mdu a* tang dan theo dd chin cimg vdi sir bien ddi mau sac ttr man xanh (DCl) ddn mau vang hm xanh (DC2) sang mdu vdng cam (DCS) va cudi cung Id mdu cam dd (DC4).
Bang 2 ciing cho thay do eung cua qua giam dan theo do ehin thu hdi. Mdu DCl va DC2, qua rat ciing vdi gid t n do cung do duoc lan lugt la 4,4 va 3,9 k g / c m l 6 DCS, dp ciing cua qua giam manh cdn 1,6 kg/cm^ vd khi bdt ddu chin (DC4) qua hoi mdm (dp Cling dudi 0,5 k g / e m ^ . Didu ndy Id do ti-ong qua hdng chiia protopeetin. Id vat hdu gdn ket cde chum
sgi xenluloza d thanh td bao, tao nen str rdn chdc ciia qua khi cdn xanh (DCl, DC2). Trong qua trinh chin, dudi tde dung cua enzyme protopeetinaza, protopeetin bi thuy phan thdnh pectin hoa tan, lam eho Hdn kdt cac te bao hi gidm, thdnh te bao trd ndn mdng, td bdo va qua bi mem dan (DCS, DC4) [5, 6].
Ciing vdi sir thay ddi ve kich thudc, mdu sac, trang thdi la su bidn ddi cac thanh phan hda ly cua qua. Hdm luong CKHTTS vd tanm giam manh theo dd ehin. DCl cd ham lugng CKHTTS va tanin eao nhat (28,40Bx va 23,9%), qua rat chat. Ddn DC2 va DCS, ham lugng CKHTTS va tanin giam nhanh xudng khoang 19,5 - 22,l«Bx va 15,5 -17,1%. O DC4, ham lupng CKHTTS va tanin ehi cdn 17,3'^Bx va 10,5%. Nguydn nhan chinh la sau khi thu hoach qua vdn tidp tuc hd hap de cung cap nang lupng nhdm duy tri cac hoat dpng sdng cua ban than chung.
Nguyen lieu ctia qud trinh hd hap la dudng, cac axit hiiu CO, chat khoang... do dd lam ham lugng CKHTTS ti-ong rau qua giam di [7, 8]. Cdn tanin la mdt hgp chat phenol trong rau qua. Tanin hda tan
37
KHOA HQC CONG N G H i
gay ra vi chat d qua hdng. Vi ehdt ciia qua hdng giam di la do cac phan iing trung hop hoae polime hda giira tanm hda tan va acetaldehyde dd tao nen phirc chat khdng tan, khdng cd vi chat [7].
Str giam ham lupng tanin cua qua hdng da duoc nhidu tac gia nghien euu trudc day. Theo mdt sd tdc gia, acetaldehyde la chat lien quan tnrc tidp ddn su khdng hda tan tanin [9,10]. Theo Yamada vd cs. Ill]
va Pesis [9] cho rdng, acetaldehyde duoc chuydn hda til pyruvate va ethanol, xuc tac Idn lugt bdi enzyme pyruvate decarboxylase va alcohol dehydrogenase.
Tuy nhidn, trong mdt nghien cim vd co che ehin cua qud hdng [8], Shiesh Ching Chang va es. cho rdng acetaldehyde khdng ehiu trdch nhiem trong viec khii chat gay ra bdi sau qua trinh chin. Chinh ndng do ethylen eao, da kich hoat qud trinh chin eua qua va su mdt nude d thanh te bao. Viec giam kha nang tham thau trong khdng bao (khdng gian cua te bao) lam mat nude td bao, do dd tanin hda tan thanh dang khdng hda tan va loai bd ehdt chat khdi qua hdng.
Ham lugng axit TS trong qud hdng kha thap. Khi qua d DCl va DC2, ham lugng axit TS khdng cd su khde biet, khoang 0,29%. Sau do, ham luong axit giam dan khi qua d DCS (0,23%) va DC4 (0,16%).
Ham lugng dudng TS tang dan theo do trudng thdnh va qud trinh chin ctia qua. O DCl, ham luong dirdng thdp nhat (khoang 10,6%), tidp dd tang ddn den DC4 hdm luong dudng dat khoang 13%, qua hoi nggt. Su tich tu cac chat dudng trong qua trinh chin khdng chi do str dudng hda tinh bgt ma edn do su thiiy phan cae chat khde nhu saccharose, cellulose, hemicellulose, pectin, lignin,... [12].
Nhu vay, ket qua phan tieh mdt sd dae tinh ly, hda cua qua hdng theo do chin thu hai cho thay hong d DCl cd kich thtrdc nho hon, ham lugng tanin va CKHTTS rat cao, ham lugng dudng TS thap hon dang ke so vdi DC2 vd DCS. Do dd, neu thu hoach d DCl, san lugng va ehdt lugng qua se thap.
3.3. Anh hudng cua dd chin thu hdi ddn cudng dp hd hap ciia qua hong sau thu hoach
Qud trinh gia hda bdt ddu khi tinh bdt vd dudng du trir trong sdn pham bi tieu thu, Tdc do Ueu thu nay duoc xae dinh qua cudng dp hd hap. Cudng dp hd hap la mdt chi tieu quan trgng dugc dung dd danh gia miic do hd hap cua ndng san trong qua trinh bao quan. Ket qua nghien ciiu ve anh hudng cua dp chin
thu hai ddn cudng dd hd hap ciia qua hdng hidn dhinh 1.
duoc the
1 2 3 5 6 7
Hinh 1. Anh htrdng cua do chm thu hdi ddn cudng dO hd hap ciia qua hdng sau thu hoach Hinh 1 cho thay, hdng thudc nhdm qua hd Mp dot bien. Trong qua trinh chin eua qua, ed su bien ddi rd ret vd cudng dp hd hap cua qua ma dae tnmg la su tang nhanh cudng do hd hap va sau do lai giam nhanh tao nen mdt dinh hd hap [13, 7, 14]. Ngay thii nhat, cde mau cd cudng dd hd hap tang theo dp chin ciia qua, mdu TN2.1 cd cudng do hd hap thap nhat la 16,32 ml COa/kg.h, tiep theo la TN2.2 (25,77 ml COa/kg.h) vd eao nhat la mdu TN2.3 (33,84 ml COj/kg.h). Mdu TN2.1 cd cudng dp hd hap dn dinh trong khoang 7 ngdy ddu va bdt ddu tang len tu ngay thii 8. Mau TN2.2 va TN2.3 cd cudng dp hd hap tang ddn va dat dinh hd hap lan lugt d cac ngdy thtr 8 (42,50 ml CO^/kg.h) va thu 5 (45,11 ml CO^/kg.h), sau dd giam ddn.
O qua hd hap dot bidn ed su tang nhanh cua cudng do hd hap cung vdi qud trinh chin cua qua.
Thdng thudng, qua d giai doan chin an dupe hoac mdm d sau dinh dot bidn. Hinh 1 cung cho thay cudng do hd hdp cua qua hdng d DCl cd thdi gian chin keo dai (khoang tren 10 ngay) keo ddi hon so vdi DC2 va DCS.
3.4. Anh hudng ciia dg chin thu hai ddn kha nang chin cua qua hdng sau thu hoach
3.4.1. Danh gii qui trinh chin ciia qui hong theo do chin thu hai
Hdng dupe thu hoach theo 4 dp chin va dd chin tu nhien d dieu kien thudng (25-30"C, RH 65-753^.
Ket qua ddnh gia qud trinh chin sau thu hoach ciia qua hdng dugc the hien dbang 3.
38 NONG NGHIEP VA PHAT TRiEN NONG THON - KY 1 - THANG 3/2019
KHOA HOC C O N G NGHE
B ^ 3. D^nh gid qud trinh chin ciia qua h6ng theo do chin a 6ihl ki^n thuorng Do chin
TN3.1 (DCl)
TN3.2 (DC2)
TN3.3 (DCS)
TN3.4 (DC4)
Ty 16 qua chin Ngay
10
15 S 7 10 15 S 6 3-4
Ty 16 qua chin
(%)
13,3
S3,3 25 64,3 85,7 100 43,0 100 100
Danh gia cam quan
- Qua chin mau do cam. Qua bi heo, mop va m6m. Kho tach num qua va vo qua. Vi chat, hoi ngot, kem thom.
- Sau 15 ngay, cac qua con lai mau xanh vang va vang ngot
- Qua chin mau do tuoi. Quii m6m, cang bong, de tach vo - Sau 15 ngay, toan bo mau chin hoan toan.
- Qua chin mau do tuoi. Qua mem, cang bong, d6 tach vo va num qua. Vi rat ngot, thom, khong chat.
- Sau 6 ngay, toan bo whi chin hoan toan.
- Qua chin mau do tuoi. Qua m^m, cang bong, d6 tach vo va mim qua. Vi rat ngot, thom, khong chat.
- Sau 3-4 ngay, toan bo mSu chin hoan toan.
Kdt qua danh gid qua trinh chin ttr bang 3 cho thay qua hdng d ca 3 dd chin DCl, DC2 va DCS deu chin khdng ddng deu. Chat lugng cam quan khi ehin cua DCl kem, qua cd bidu hidn chin dp va sau 15 ngdy, ty Id qua chin ehi dat 33,3%. Qua hdng d DC2 va DCS khi chin ed chat Itrong cam quan tdt tuong ttr nhu DC4. Todn bd mdu DC2 chin hodn todn sau 15 ngdy vd mdu DCS la khoang 6 ngay. Trong khi dd.
qua hdng DC4 cd kha nang chin khd ddng deu, qua chin hodn toan sau 3-4 ngay d dieu kidn thtrdng.
3.4.2. Anh hudng cua do chin tbu bii den chat lupng chin ciia qui hdng sau thu hoaeh
Kdt qua phan tich chat lugng chin eua hdng d didu kidn thudng theo do chin thu hai dugc thd hien trong bang 4.
Bang 4. Anh huong ciia dg chin thu hai d^n chat luong chin cua qua h6ng sau thu ho$ch Chi heu chat luong
1. Do cung (kg/cm^) 2. Mau sdc
L*
a*
b*
3. TSS (°Bx)
4. Ham luong axit hiJu coTS (%) 5. Ham luong duong TS (%) 6. Ham luong tanin (%)
7. Cam quan
TN3.1 (DCl)
<0,5 46,59+1,47 27,99 + 3,94 39,50 ± 2,67 18,1+0,2 0,15 ±0,04 10,40 + 0,03 3,80 + 0,15 - Qua chin man do cam. Qua bi heo, mop va mem. Kho tach mim qua va vo qua.
- Vi chat, hoi ngot, kem thom.
TN3,2 (DC2)
<0,5 34,73 + 1,19 22,11 ±1,08 17,11 + 1,94 14,5 + 0,5 0,13 ±0,01 14,23 ±0,17 0,25 ± 0,04 - Qua chin mau do tuoi. Qua m6m, cang bong, d6 tach vo va mim quii.
- Vi rat ngot, thom
TN3.3 (DCS)
<0,5 34,60 ±0,31 12,03+1,69 17,84 ± 1,27
14,7 ±0,6 0,12 + 0,01 14,35 ±0,12 0,27+0,02 - Qua chin mau do tuoi. Qua m6m, cang bong, dk tach vo va mim qua.
- Vl rat ngpt, thom
TN3.4 (DC4)
<0,5 34,12 + 0,94 22,00 ± 0,55 17,14 + 0,60 15,0 + 0,2 0,13 ± 0,02 14,56 + 0,20 0,25 ± 0,03 - Qua chin mau do tuoi. Qua mem, cang bong, dg tach vo va mim qua.
- V| rat ngot, thom
39
KHOA HOC CONG N G H l
Ttr bang 4 cho thay qua hdng d DCl khi chin cd ham lirong dudng tdng sd thdp (10,40%), ddng tiidi ham lugng CKHTTS va tanin cao hon nhidu so vdi cac do chin cdn lai, lam qua vdn cd vi chat va chi hoi ngpt, kem thom. Qua cd bieu hien chin dp, chat lugng chin kem.
6 DC2 va DCS, tiiy qua chin khdng ddng deu nhung chat lugng chin cua qua tdt hon DCl rat nhidu va khdng khac bidt so vdi mdu qua chin cua DC4.
Cac mdu qua DC2, DCS va DC4 khi chin eho ehdt luong cam quan rat tdt: qua cang bdng, dd tuoi, dd dang tach mim va vd qua, ddng thdi vi rat ngpt va khdng cdn cam gidc ehdt do ham lugng tannin rat thap (0,25-0,27%) va ham luong dudng kha cao (14,23-14,56%). Khi hdng chin hodn toan, CKHTTS ciia qua giam edn 14,5-15,0°Bx, vd ham lugng axitTS chi cdn khodng 0,13%.
Nhu vay, qua ket qua nghien ciiu xac dinh edc dae tinh ly, hda cua qua hdng khi thu hai d cac DCl, DC2, DCS, ddng thdi ddnh gia qua trinh chin tu nhidn ciia qua hdng d ca 3 dd ehin (so vdi DC4), da dua ra kdt luan ve lira ehgn do ehin thu hai phti hop vdi mue dich, thi trudng tieu thu ctta sdn pham qua hdng tuoi nhu sau:
r Khdng nen thu hoach hdng khi qua d DCl vi d dp chin nay nang sudt thu hoach thdp, ddng thdi chat lugng chin sau thu hoach rat kem, qua hi chin dp.
> Ndu tieu thu qua hdng d thi trudng gdn, khdng can bao qudn thi DCS la thich hgp do cho ty le qua chin cao Q-ong thdi gian ngdn, va chat lugng chin tdt (tuong duong vdi chat lugng chin cua DC4).
^ Tuy nhidn, de tieu thu thi trudng xa vd/hoac cdn keo dai thdi gian tdn ti-ti hdng sau thu hoach thi DC2 la phii hgp nhat, do eho chat lugng chin vdn tdt (tuong duong vdi chat lugng chin ciia DCS va DC4).
4 . KET LUAN
Dae tinh cua qua hdng Thach That Id loai qua hd hap dot bidn, cudng do hd hap dat cue dai la 45,11 ml CO^/kg.h d didu kien mdi tiordng nhiet dp 25-30"C va do am 65-75%.
Dp chm thieh hgp nhdt de thu hai qua hdng la DC2, khi qud cd mim mdu vdng xanh tuoi, mau qua vang (>80%) vd cd mau vang boi xanh d dudi qua (<20%), qua cung gidn, vi rat chat, ehira ngpt, min ehua rd, dat 100-110 ngay tudi tir khi dau qua. Ddng
thdi d DC2, cac chi tieu ly hda cua qLia hdng nhir ham luong dudng tdng so, ham li/dng ''^*' ^ ^ lugng tanin bien ddi theo chidu huong n^°"S murfa Khi thu hoach d do chin nay se diuan hon de v^
chuyen den noi tieu thu ddng thdi keo dai thdi gian sir dung qua hdng sau thu hoaeh.
TAI LEU THAM KHAO
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40 NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THANG 3/2019
KHOA HOC CONG NGHE
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^ * ' ° * ' ^ ' - Minh. 82.
THE EFFECTS OF RIPENING STAGES ON SOME OF THE SPECIFICPHYSYSrCOCHEMICAL PROPERTIES OF THE THACH THAT PERSIMMONS
Nguyen Thi Hauh', Vu Thi Nga^
^Institute of Biology and Food Technology, School of Hanoi University of Science and Technology
^Lnstitute for Agricultural Engineering and Post Harvest Technology Summary
The purpose of this study was to determine the effects of ripening stages on some of the specific physicochemical properties and maturity of the Thach That Persimmons (Diospyros Itaid Tliunb.) for proposing the most appropriate harvesting hme for this fruit. Physical and chemical properties are specified, including: respiratory intensity, size, mass, hardness, color, total dry matter content, sugar content, total acidity and total tannin content of persimmon fruit. The results showed that the most suitable maturity for picking up the persimmon fruit is when the fruit has a yellow-green stalk, yellow skm (> 80%) and slightly yellowish at the fruit bottom (<209(>), crunchy flesh, very harsh, not sweet, slight odor, and at 100-110 day age from fruiting time.
Keywords: Persimmon fruit, harvesting time, respiratory intensity, postharvesting.
Ngudd phan bita: PGS.TS. Hoing Thi L6 Hang NgiynhlUi bii; 28/11/2018
Ngiy thang qua phan bita: 28/12/2018 Ngiy duyet dang: 4/01/2019
